Breathing apparatus, such as powered air purifying respirators (PAPR), are generally used in polluted environments to provide filtered, non-toxic air to a wearer. A PAPR device typically comprises a flow generator for generating filtered air, and a mask for communicating the filtered air to the wearer. The flow generator typically comprises a powered impeller arranged to draw air from the atmosphere and a filter assembly including a filter element through which the air is passed and filtered. The filtered air is then conveyed to the wearer via the mask.
The filter assembly typically comprises a housing adapted to receive and retain one or more filter elements, and respective one or more filter elements. The filter elements are typically releasably engaged with the housing to allow replacement when an element is clogged or otherwise expired, or to allow one filter element to be substituted with another due to particular filtering characteristics of the filter element being most suitable for the environment the breathing apparatus is being used in. The filter assembly often further comprises a pivotable cover for accessing a recess in the housing into which the filter element is arranged, and covering the filter element when installed in the housing to prevent undesirable water ingress.
Breathing apparatus often utilise various different types of filter elements dependent on the ambient environment in which the breathing apparatus will be used. For example, the filter assembly may one or more of: a coarse filter; a pre-filter; a high efficiency particulate air (HEPA) filter; an advanced carbon filter; an activated carbon filter (steam activated or multiple chemical activated); a photo catalyst filter or coating (ambient light and/or LED activated); and/or a cold catalyst filter.
It is therefore critical to the function of the breathing apparatus, and potentially the health of the user, that a filter element is installed in the filter assembly, and may also be critical that the correct type of filter element able to provide particular filtering characteristics is installed. However, both of these requirements can prove problematic as the arrangement of a filter element in a breathing apparatus often means that it is difficult for a user to view the filter element and therefore determine if the filter element is present. It is also often inconvenient to determine whether the installed filter element is suitable for the environment the breathing apparatus will be used in, often requiring the filter element to be removed and inspected.
During use of such a breathing apparatus, it is also common for the filter element to become ‘blocked’, i.e. full of particulates and/or contaminants, and therefore unable to provide the filtered air to the user. Whilst conventional breathing apparatus often provide a ‘filter blocked alarm’ which is activated when the filter is fully blocked, such alarms are only activated when the filter is entirely blocked, meaning that a breathing apparatus can be unusable shortly after a user has fitted the apparatus and entered a polluted environment, which can further inconvenience the user.
Accordingly, it would be useful for a filter assembly, or a breathing apparatus including a filter assembly, to confirm to a user whether a filter element is installed in the filter assembly, and potentially also confirm the type and/or characteristics of the filter element, and/or how blocked or full of particulate the filter element is. Furthermore, it would be useful to provide a solution that avoids or ameliorates any of the disadvantages present in the prior art, or which provides an alternative to prior art approaches.